in your setup, it looks like you've set static pressure at both ends of 101325? a better choice would be environmental pressure at both ends if you're trying to simulate them being open to atmosphere. take a look at the help for more info on static pressure vs environmental pressure. in an ideal situation, you could make this an internal/external analysis where those ends are open to environement completely. (a worthwhile test to compare your boundary conditions against)

I don't fully understand this comment:

Theoperating pointthat is definedbythe system curveand thecharacteristic curve of thefanis:flow of 115m³/h andpressure of 600Pa.

But what I can tell you is how flow simulation is solving the problem. The simplest way your curve is defined is if there is zero pressure difference on either side, your fan will perform at full volume flow rate. If it is completely choked, you'll get zero volume flow rate. As the software is solving your problem, it is solving for the pressure on both sides of your fan and comparing the difference against your curve to generate the flow rate. It is an iterative process.

So what you might want to do is create a goal on both sides of your fan for static pressure (or total pressure depending on how you defeined it) and then an equation goal for the difference. Compare that against your fan curve. it should match the flow rate leaving your fan. if it isn't, it could be a mesh issue or it could be a reference density issue.

so in essence, there is no way to set the operating point. your systme defines what the operating point is. just like in the physical situation. if you wanted to set the operating point, you would simply set a volume flow rate.

I am using this feature as well. The fan data at operating point (flow & pressure) come from fan manufacturer. They are input in SWFS using fan feature tables & curves, and setup as a goal to be monitored. After a few steps running shows a descrepency of flow rate comparing with original data. Then adjustment is made on the original data until the flowrate is matching required one. This should simulate the real situation of internal flow, expecially if you calculate the internal component's pressure drop.